Image display from continuously moving image carrier

ABSTRACT

A method of and apparatus for displaying images of a succession of recordings from a substantially continuously moving carrier operates with an optical compensator of a type being repeatedly advanced and being reset between successive advancements. Each image is displayed by way of the compensator and the compensator is advanced during the display of each image to compensate for the continuous carrier movement. The time for resetting of the compensator is determined by sensing extreme advanced position of the compensator. The compensator is then reset in response to each sensing of an extreme advanced position.

United States Patent [191 Cooper, Jr,

[ 51 Feb. 27, 1973 IMAGE DISPLAY FROM CONTINUOUSLY MOVING IMAGE CARRIER [75] Inventor: Dexter P. Cooper, Jr., Pasadena,

Calif.

[73] Assignee: Bell 81', Howell Company, Chicago,

22 Filed: Jan.11,197l

21 Appl.No.: 105,571

[52] US. Cl ..352/109, 352/110 [51] Int. Cl. ..G03b 41/10 [58] Field of Search ..352/92, 109, 110; 318/640;

[ 56 References Cited UNITED STATES PATENTS 7/1958 Tyler ..352/109 11/1970 Johnston ..352/109 12/1970 John, Jr ..352/92 12/1962 Baldwin ..352/ 109 Primary Examiner-Samuel S. Matthews Assistant ExaminerRussell E. Adams, Jr. AttarneyLuc P. Benoit [57] ABSTRACT A method of and apparatus for displaying'images of a succession of recordings from a substantially continuously moving carrier operates with an optical compensator of a type being repeatedly advanced and being reset between successive advancements. Each image is displayed by way of the compensator and the compensator is advanced during the display of each image to compensate for the continuous carrier movement. The time for resetting of the compensator is determined by sensing extreme advanced position of the compensator. The compensator is then reset in response to each sensing of an extreme advanced position.

37 Claims, 10 Drawing Figures- PATENTEB FEB 2 7 I975 SHEET 3 BF 5 m w u 3 W6 mm v 5% PATENTEnrmzmn SHEET 5 OF 5 m l m m$ ST IMAGE DISPLAY FROM CONTINUOUSLY Movmo IMAGE CARRIER BACKGROUND OF THE INVENTION brothers Lumiere proposed a motion picture apparatus Shortcomings of mechanical cams subsequently fostered a search for corresponding electronic means for initiating and controlling the advance and resetting of the compensator element. Employment of electronic means called for the provision of a sensing device which would initiateresetting of the compensator element.

A typical proposal for meeting this need made use of the fact that the timing of the compensator element resettings can to a large extent be determined from the arrival of film sprocket holes or other fiducial markings at a specific location near the frame projection aperture. According to that proposal, the film margin bearing the sprocket holes or I fiducial markings, is illuminated through a monitoring aperture in the film gate. A photocell located at the film gate then senses the arrival of sprocket holes or fiducial markings at the monitoring aperture.

While that prior-art proposal generally presents a workable solution, it does have its drawbacks. One of these resides in the fact that space at the film gate is frequently limited, particularly if a small film format is used. Moreover, toavoid interference of the photocell sensing equipment with the image display, and with the image display compensator control, it is necessary that the reset sensor operate in response to a sprockethole or fiducial marking that, belongs to an image other than the image being displayedThis implies the danger that vide for a control of that element during image display operations. The latter proposal presents a workable solution but is limited in its application to situations in which the shutter operation is accurately correlated to the film advance, independently of the compensator element operation, and in which the compensator element control system is capable of operating with the same photocell for compensator control and compensator resetting purposes.

SUMMARY OF THE INVENTION The subject invention overcomes or materially alleviates these disadvantages by a radical departure from the prior-art course of development.

From one aspect thereof, the invention is concerned with a method of displaying images of a succession of recordings from a substantially.continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements. The invention according to this aspect resides in the improvement comprising in combination the steps of displaying each image by way of the compensator, advancing the compensator during the display of each image to compensate for the continuous carrier movement, sensing an extreme advanced position of the compensator, and resetting the compensator between successive advancements in response to each sensing of said extreme advanced position.

In this manner, the subject invention correlates the timing of the compensator resetting operations to a a compensator resetting operation is initiated prior. or

subsequent to the actual termination of the display of the particular image.

Another prior-art proposal triggers resetting operations by sensing the rotational position of a sprocket which is geared to the motion picture film. Disadvantages of that proposal include the fact that the employed sprocket imposes mechanical wear and tear on specific state of advancement of the compensator. This avoids the prior-art need of resetting sensors at the film gate or at a film sprocket, and also presents a solution that is more universally applicable than the above mentioned shutter-initiated resetting control.

In accordance with a preferred embodiment of the subject'invention, the extreme advanced position ofthe compensator is sensed by providing a projectable stimulus, projecting this stimulus by way of the compensator, and sensing the projected stimulus to determine attainment of the extreme advanced position by the compensator. The expression projectable stimulus is herein employedas a generic term covering any manifestation of radiant energy that can be projected by way of the compensator and can be sensed upon such projection. Examples of suitable projectable stimuli include beams of visible light or beams" of infrared or ultraviolet radiation. I

Another aspect of the subject invention is also concerned with a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements. According to this aspect of the subject invehtiom'eachimage is displayed by way of the-compensator. The compensator is .ad-

vanced during the display of each image to compensate In accordance with a further aspect of the subject invention, which is also concerned with an image display method of the above mentioned type, each image is again displayed by way of the compensator, and the compensator is advanced during the display of each image to compensate for the continuous carrier movement. A first projectable stimulus and a second projectable stimulus are provided and are projected by way of the compensator. Reset initiation energy is generated for the compensator in response to the first projected stimulus upon completion of the display of an image. A resetting operation of the compensator is initiated with that reset initiation energy. Reset sustaining energy is generated for the compensator in response to the second projected stimulus, and the initiated resetting operation of the compensator is sustained with the resetsustaining energy. I

A further aspect of the subject invention, which is also concerned with an image display method of the above mentioned type, provides a first projectable stimulus emanating from a location substantially stationary relative to the moving carrier, andproyides a second projectable stimulus being movable with the moving carrier. Each image is displayed, and the first and second stimuliare projected, by way of the com- :vance of the compensator is controlled inresponse to the projected second stimulus during the display of each image to compensate for the continuous carrier movement. Resetting energy is generated for the compensator in response to the projected first stimulus upon completion of the display'of any image, and the compensator is reset with that resetting energy.

A preferred embodiment of the latter method includes the further steps of generating reset decelerating energy in response to the projected second stimulus preparatory to the display of a succeeding image, and decelerating the resetting compensator with that reset decelerating energy.

The subject invention also resides in apparatus for displaying images of a succession of recordings from a carrier. According to the invention, these apparatus comprise the combination of means for substantially continuously advancing the carrier, means for displaying each of the images, including optical compensator means, means for advancing the'compensator means during the display of each image to compensate for the continuous carrier movement, means for sensing an extreme advanced position of the compensator means and means connected to the sensing means for resetting the compensator means between successive compensator means advancements in response to each sensing of said extreme advanced position.

The subject invention moreover resides in various apparatus for carrying out the above mentioned or similar image display methods. These apparatus will become apparent in the further course of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS The subject invention will become more'readily apparent from the following detailed description of preferred embodiments thereof, illustrated by way of example in the accompanying drawings, in which:

FIG. 1 is a diagrammatic illustration of a non-intermittent or continuous motion picture projector according to a preferred embodiment of the subject invention;

FIG. 2 is a view along lines II-Il of FIG. 1;

FIG. 3 is a circuit diagram of a resetting pulse generator and an image motion sensor of the projector of FIG. 1;

FIG. 4 is a circuit diagram of a servo amplifier and mirror drive of the projector of FIG. 1;

FIG. 5 is a top view of a photocell combination that may be employed in the image motion sensor of FIGS. 1 and 3;

FIG. 6 is a side view, partially in section, of a compensator mirror and mirror drive for use in the apparatus of FIG. 1;

FIG. 7 is a view along lines VII-VII of FIG. 6;

FIG. 8 is a diagrammatic illustration of a non-intermittent or continuous motion picture projector according to a further preferred embodiment of the subject invention,

FIG. 9 is a perspective view, on an enlarged scale, of a sensor in accordance with a preferred embodiment of the invention, for ,use in the apparatus of FIG. 8; and

FIG. 10 is a signal amplitude-versus-time' plot, qualitatively illustrating a function of the sensor of FIG.

Like reference numerals in the drawings designate like or functionally equivalent parts. 1

DESCRIPTION OF PREFERRED EMBODIMENTS I The subject invention is of broad utility in continuous film motion display systems with resettable motion compensator means, and is not limited in its applicability to any specific system. However, to present the best mode presently contemplated of carrying out this invention, the preferred embodiments are herein disclosed and illustrated with reference to the system of US. Pat. application Ser. No. 89,323, filed Nov. 13, 1970, by Ellen B. Lancor, Administratrix of Joseph H. Lancor, Jr., deceased and by Leonard A. Ferrari, and assigned to the subject assignee, and herewith incorporated by reference herein.

The non-intermittent or continuous motion picture projector 10 shown in FIGS. 1, 2, 3 and 4 has a film gate 12 which may be curved in accordance with wellknown principles rendering the angular rate of film advance equal for different points of the film gate.

A conventional variable speed drive 15 has a capstan 16 which may have a rubber lining 17 that engages the film with the aid of anip roller 18. The drive'lS, which may comprise a variable-speed electric motor with reduction gear (not shown), is set at any practical speed to advance a motion picture film 13 through the film gate 12 in the direction of an arrow 19 at a substantially continuous or uniform rate (as distringuished from an intermittent film advance). Two guide rollers 20 and 21 assist the movement of the film into and out of the film gate.

In principle, a sprocket drive can be used for advancing the film 13. Where film sprocket holes are employed as control marks, it is, however, preferred that a capstan which does not wear out the sprocket hole areas be used as the power-transmitting device.

The film l3 bears a succession of optically reproducible recordings in the form of transparent images 23 located in image frames 24 and typically representing a filmed scene. The film further has sprocket holes 25 along a margin 26 thereof. In accordance with known principles, the film gate has a projection aperture 28 whose length is at least equal to twice the height of each image frame 24 plus the height of an interframe space 29, so that the continuous motion compensator 30 is able to handle two full image frames in succession. The width of the projection aperture is sufficient for a projection of the sprocket hole that pertains to each projected image.

Working with projected sprocket holes through which light is transmitted presupposes that the. film margin 26 is opaque or black. This typically is, indeed, the case 'if the film was produced with a reversal development process. If the sprocket hole margin 26 is transparent, a non-reflecting background may be provided behind themargin 26 and light may be projected onto the margin 26. This projected light is reflected by the film in the margin 26, but not by the sprocket holes. Accordingly, instead of sensing luminous sprocket hole images against a dark background, luminous background areas relative to dark sprocket hole images may be sensed in order to determine relative motion of the projected image (see Pat. No. 3,067,284, by -.I.L.E. Baldwin, issued Dec..4, 1962, and herewith incorporated by reference herein). Alternatively, a transparent margin of the film may be provided with opaque spots which accompany corresponding image frames 24, and which are sensed against luminous background areas. r

The film 13 at the projection gate 28 is illuminated by a projector lamp 32 and condensor lens system 33. The lamp 32, which may have a conventional reflector (not; shown), is energized from an electric power source 34 upon closure of a switch 35. A projector lens system 38 projects the illuminated images and sprocket holes-by way of the continuous motion compensator onto a conventional back-lighted screen 39.

The compensator 30 has a first-surface mirror 40 which is repeatedly advanceable by motive power applied to a coil 41 through a range of angular motion so as to compensate for the continuousmovement of the film .13. The objective of the compensator mirror 40 is to maintain each projected image substantially stationary. Since the projection aperture 28 in the film gate 12 is larger than an image, the screen 39 is provided with an opaque frame 43 which blocks from the view of the observer the projected sprocket holes and also parts of images other than the one image that is I being projected for viewing at the particular time.

A device 45 is located at the screen for sensing relative movements of each displayed image in a first direction corresponding to the direction '19 of movement of the film '13. The device 45 also senses relative the photocells 47 and 48. Each of the photocells 47 and 48 produces a signal which varies as a function of the area of cell illumination.

As shown in the schematic of FIG 3, the cells 47 and 48 are connected in parallel and at opposite output voltage polarities between two terminals 50 and 51 of the sensing device 45. The two output voltages of the cells 47 and 48 buck each other, producing no net voltage across the terminals 50 and 51 when the photocells 47 and 48 receive equal portions of a projected sprocket hole 53. In the case of projected luminous sprocket holes, the cells 47 and 48 produce zero net voltage in response to equal illumination by portions of the projected sprocket hole. In the case of dark sprocket holes projected with a luminous background surrounding each dark hole, the cells 47 and 48 produce zero net voltagein response'to equal illumination byportions of the luminous background above and below the projected sprocket hole.

It may be helpful to note at this juncturethat the sensor 45 need not necessarily be located at the screen 39. Rather, the sensor may be positioned closer to the compensator mirror 40 (such as within the projector housing), with a lens (not shown) being provided for imaging the illuminated sprocket hole onto the sensing device 45 projection thereof by way of the mirror 40.

The projector 10 further includes an amplifier 55 for energizing the compensator coil 41 that moves the mirror 40. In the system shown in the drawings, no routine sawtooth motion is imposed on the compensator mirror 40. Rather, the mirror is only advanced in accordance with the then prevailing demands of the system aiming at a stabilization of displayed images in a substantially stationary condition.

To illustrate thisprinciple, a dotted line a-in FIG. 1 approximately designates a ray of light emanating from the center of an image 23 initially appearing in the aperture 28 of the film gate 12 for projection by the objective 38 and via the compensator mirror 40 onto the screen 39. A dotted line b, on the other hand, approximately designates a ray of light emanating from the center of the same image, after that image has traveled along the film gate 12 to its extreme position in the aperture 28, just before the compensator mirror 40 is reset onto the next succeeding image. The stop plane of the lens 38 is preferably in front of the lens near the mirror 40.

The letter c in FIG. 1 designates a ray of light leading from the compensator mirror 40 to the center of the projected image on the screen 39. To maintain each projected image stationary during the movement of the image center lines from a to b, the mirror has to advance during such movement by an angle of a magnitude substantially equal to one-half of the magnitude of the angle between the lines aand b. i

To provide for such a mirror advance, the mirror 40 is wide enough to receive and project images of the sprocket holes 25 which are illuminated by the projector lamp 32. Where the mirror 40 operates in collimated light, as is preferably the case, reduction of the mirror size reduces the total light level but does not as such block passage of the sprocket hole image. As indicated above, each of these projected sprocket hole images impinges on the sensing device 45; one, at a time. This device senses relative movements of the .pro-

jected image by developing a net error voltage in response to movements of the projected sprocket hole images relative to the sensing device 45. This error voltage is applied as an input voltage to the servo amplifier 55.

The latter input voltage causes the, amplifier 55-to develop and apply to the compensator coil 41 motive power for angularly moving the compensator mirror in such a sense as to reduce movement of the projected sprocket hole in the named first direction. As is typically the case with practical servo systems of simple design, the mirror 40 will inevitably tend to overshoot in the direction of its advance.

As has been disclosed in the above mentioned Lancor and Ferrari patent application, and as will be more fully mentioned below, a direct-current level is applied to the servo amplifier 55 in order to provide for a biasing of the mirror 40 in a direction opposite to the direction of mirror advance during the display of each image. This has the very important advantage of obviat-' ing the need for the traditional bias spring at the mirror 40 or of at least permitting the use of only a weak, mirror suspension or bias spring. If no mirror bias spring is used, the amplifier 55 does not'have'to provide a mirror drive current that increases in a sawtooth fashion to overcome the force of a mirror bias spring'as the display of the image progresses. Similarly, if a spring of low spring constant is used for mirror suspension or other purposes, the servo amplifier 55 still does not have to provide a mirror drive current that rises to as high a magnitude as would be required if the spring had a sufficieritly high spring constant to effect an automatic resetting of the mirror 40 between image displays or'to act as the sole agency for precluding overshooting of the mirror 40 during image display.

In addition, the amplifier 55 is constructed to develop and apply to the mirror drive coil 41 a decelerating current when a large excursion of the net error voltage developed by the sensing device 45 indicates the danger of ringing of the servo system. These features are more fully disclosed in the above mentioned copending Lancor and Ferrari patent application. Also, it should be understood that systems which generate sawtooth currents for driving the compensator mirror 40 may, if desired, be employed, since the practice of the subjectinventor is not limited to the illustrated projector system.

The preferred circuit diagrams of FIGS. 3 and 4 will now be considered.

According to FIGS. 3 and 4, the motion sensing device 45 may be connected to the amplifier input terminal 56 through resistors 60 and 61 and a terminal 62. The resistor 60 is adjustable to render the loop gain variable. A capacitor 63 is connected in parallel to the resistors 60 and The combination of resistors 60 and 61 and capacitor 63 provides an electric damping network.

A preferred amplifier 55 is illustrated in FIG. 4 and comprises an operational amplifier 64 and a complementary emitter follower output stage 65 Those skilled in the art of integrated circuits will recognize that the operational amplifier 64 is available in monolithic form from several manufacturers as standardized circuit 1709 (for L instance, MOTOROLA OPAMP MC1709C). Accordingly, a detailed elaboration on the circuit diagram of opamp 64 beyond its illustration in FlG. 4 is unnecessary.

The output stage of the amplifier 55 is a conventional complementary emitter follower stage that also does not require any special elaboration as to its circuitry. The feedback path 67 for the amplifier 55, with a feedback resistor 68, is connected between the amplifier 69 and the amplifier input 56. Thecompensator coil 41 is connected to the amplifier output 69. The supply voltage stabilizer with Zener diodes 71 and 72 andfilter capacitors 73 and 74 is also conventional.

The requisite direct-current level for biasing the mirror 40 in a direction opposite to the direction of mirror advance during image display is provided by developing a direct current potential with the aid of a potentiometer 108. This potentiometer is connected between the +15 volt and -l5 volt terminals of the current supply. The slidable contact of the potentiometer 108 is connected to a further input A of the servo amplifier 55 or operational amplifier 64. In this manner, an adjustable current is provided in the drive coil 41 for biasing the compensator mirror 40 in.a direction opposite to or against'the direction of mirror advance during image display. x l i During image display, undesired image movements are easily reduced by increasing the gain of the ampli fi-- higher than 100 and may er 55. This gain is preferably be in the thousands.

Upon completion of the display of an image, the compensator mirror 40 isangularly reset preparatory to the display of the next image. As disclosed in the above mentioned copending Lancor and Ferrari patent application,'timed electric pulse doublets areapplied to the compensator coil 41 for resetting the mirror 40 between image displays. 1f the polarity of the mirror advance driving power is considered positive, then the resetting doublet illustrated in FIG. 3 comprises a negative pulse 81 followed by a positive pulse 82. The negative pulse 81 angularly drives the mirror 40 backwards at high speed, and the succeeding positive pulse 82 of the doublet prevents an overshooting of the mirror 40 in the reverse direction. This does away with the necessity of a mechanical stop or motion arresting device which as proved its demerits in prior art systems as a fertile source of wear and tear, noise, jitter and other trouble.

According to the subject invention, resetting of the compensator is effected in response to a sensing of a predetermined state of advancement of the compensator. In the illustrated preferred embodiment, a small second aperture 78, best seen in FIG. 2, is provided in the film gate 12 in addition to the larger image aperture 28. The aperture 78 is disposed laterally of the trajectory of the film 13 through the image gate 12. This is a factor which distinguishes the aperture 78 frompriorart monitoring apertures that were positioned within the film trajectory for the sensing of sprocket holes. No sprocket holes need to traverse the aperture 78.

The projector lamp 32 and condensor lens 33, which primarily serve to illuminate the images 23 and sprocket holes 25 within the image aperture 28, also illuminate the aperture 78. If desired, a light source (not shown) which is stationary relative to the compensator mirror 40 can be provided in lieu of the illuminated aperture 78. While this is still within thescope of the subject invention, I presently prefer the aperture 78 since it takes up less space and is cheaper than an extra light source.

The illuminated aperture 78 provides a stimulus that can be projected by way of the mirror 40 and that can be subsequently be sensed. More specifically, light 79 from the illuminated aperture 78 isprojected by the objective 38 onto the mirror 40 along with light from the images 23 and sprocket holes 25 within the image aperture 28. The mirror 40 reflects the light beam 79 along with the light from the latter images and sprocket holes. In this manner, each illuminated image and corresponding sprocket hole, as well as light from the aperture 78, are displayed by way of the compensator mirror40.

'In the embodiment of FIGS. 1 and 2, the-light beam 79 emanating from -the. illuminated aperture 78 proceeds after reflection by the mirror 40 along the trajectory d when the mirror 40 is in its solidly illustrated initial position. As the mirror 40 advances during the display of an image, the reflected light beam is swept through a vertical plane from the trajectory d to a trajectory e (in reality, the trajectories d and e are straight. They are, however, shown laterally offset to avoid too small an'illustration of the projection screen 39). The reflected light beam 79 proceeds along the trajectory e when the compensator mirror 40 has been advanced from its initial position to its extreme advanced position indicated by a dotted line 40'. The mirror position 40"is reached upon each completion of the display of an image.

A sensing device 85 senses the attainment of the extreme position 40' by the mirror 40. To this effect the sensing device 85 is located on the trajectory e. By way of example, the sensing device 85 may be located at the projection screen 85 to the side of the area onto which the images 23 from the film l3 areprojected. Alternatively, thesensing device may be situated closer to the mirror 40 than to thescreen'39. In that case, an auxilia- 55. The amplitudes of the spikes 100 are such as to drive the amplifier 55 into saturation. This is an important feature since it dispenses with the need of a circuit for disconnecting the image movement sensor 45 during mirror resetting operations. In other words, the oppositely poled spikes 100 not only provide for the requisite pulse doublets, but also effect an automatic 1 suspension of the control operation of the image movement sensor 45 during mirror resetting operations.

An arrow 102 adjacent the spike signal 100 symbolically leads to the pulse doublet 80 as it appears at the output 69 of the amplifier 55, and as it is applied'to the compensator coil 41 to initiate and timely terminate the requisite mirror flyback preparatory to a display of the next image. It is thus seen that the sensing device 85 senses a predetermined state of advancement of the compensator 30, and that the doublet generator 84 and amplifier 55 thereupon reset the compensator 30 preparatory to the display of the next image. A potentiorneter 96 permits the width of the pulse 95 to be adjusted. This, in turn, permits an adjustment of the net ry lens not shown) should preferably be used in order to project the light 79 reflected bythe mirror onto the sensor 85.

It will thus be recognized that the sensing device 85 I in: effect senses the attainment of the extreme mirror position40' by sensing the attainment of the trajectory e by the light beam 79 emanating from the illuminated aperture and reflected by the compensator mirror 40.

According to. FIG. 3, a conventional photosensor darlington circuit 88 may for instance be employed in the sensor 85. Upon being hit by light 79 reflected along the trajectory e, the darlington 88 emits an electric current following a curve of the type shown at 90 in FIG. 3. A differentiator circuit 91 produces a spike 92 in response to the current shown by the curve 90. A second differentiation spike, that would arise upon cessationifof'the illumination of the darlington 88, is shown in dotted outline, since it is suppressed by the diode in the diffe'rentiator 91.;

The spike 92 drives a one-shot multivibrator 94 of a conventional typeto produce a pulse 95. The pulse 95. is applied to -a differentiating" network 99 to produce thetwo oppositely poled spikes 100 shown at the terminal6 2. I TheterrninaI-62 being connected tothe amplifier input 56, the spike signal 100 is applied to the amplifier energy with which reversed.

Upon completion of the mirror resetting, the servo system including the photosensor 45 and amplifier 55 commences to lock in on the sprocket hole image belonging to the next succeeding image 23. Because of its the compensator mirror 40 is illustrated construction the amplifier 55 is capable of I generating decelerating power which is applied to the drive coil 41 to overcome large overshoots of the mirror 40. In general, however, the subject servo system can be made to operate so well that the above mentioned direct-current level (see potentiometer 108 FIG. I

compensator mirror 40 is cemented on a headpiece 120 of non-magnetic materiaL'In a prototype of the illustrated compensator, the headpiece 120 is made of Delrin, an .acetal resin made by E.I. Du Pont De Nemours 8c Company. The compensator drive coil'4l is wound on a tube 122 which is cemented to the headpiece 120. The tube 122 is of non-magnetic material. In

principle, the tube may be of an electrically conducting material, such as aluminum, to provide for electrodynamic damping of the compensator. The tube 122 partially extends in air gaps 123 and 124 of a magnetic armature 126.

The armature 126 comprises a yoke 127 of soft magnetic material with permanent-magnet pole pieces 128 and 129. A post 130 of non-magnetic material (such as a hard plastic resin) is mounted on the yoke 127. A

carries a small steel ball 137 or 138. These steel balls act as pivots which mount the headpiece 120 for angular movement about an axis 140. To this effect, the headpiece 120 has small cavities 142 and 143 for receiving the steel balls 137 and 138. If desired, the steel balls may be replaced by semicircular projections of the springs 134 and 135.

Considering FIGS. 6 and 7, it will benoted that the mirror 40, winding 41, headpiece 120, and tube 122 form a driven part of the compensator which is mounted for angular movement about the axis 140. There is no bias spring on this driven part. It should, however, be understood that the subject invention is also applicable to systems with spring-biased compensators. The steel balls 137 and 138 exert frictional damping on the driven compensator part which leads to an advantageous constant tracking error.

The non-intermittent or continuous motion picture projector 10. of FIG. 8 is similar to the projector 10 shown in FIGS. 1, 2, 3 and 4. Accordingly, the above disclosure of the latter figures should be consulted for an understanding of the function of those parts which I pensator mirror 40 than the projection screen 39, a lens 152 is provided for projecting the illuminated sprocket holes reflected by the mirror 40 onto the sensor 150. The lens 152 also projects the light stimulus 79 after reflection thereof by the mirror 40 onto the sensor 150. As mentioned above, the light stimulus 79 emanates from the film gate aperture 78 which is stationary relative to the moving film 13. The projected sprocket hole images emanate, of course, from sprocket holes which move with the advancing film 13. The sensor 150 is so positioned laterally of the center line c that no part of the projected image is obscured by the sensor 150.

The sensor has two compartments 154 and 155 separated by a wall 156. A photocell 158 is located in the compartment 154, and a photocell 159 is locatedin the compartment 155. The photocells 158 and 159 are differentially interconnected as shown so as to provide substantially zero net output when both photocells are equally illuminated. Trimming resistors of a conventional type may be employed for an adjustment of the quiescent value of the sensor signal. A lead 160 applies the output signal of the sensor 150 to the input 56 of the servo amplifier 55.

The nature and operation of the sensor output signal will best be understood from a joint consideration of the FIGS. 8, 9 and 10. As seen in FIG. 9, the sensor 150 has a facing plate 162 provided with a number of apertures 164, 165, 166, 167 and 168. These apertures form what may betermed an aperture logic which performs sensing and control functions with the aid of the photocells 158 and 159 enclosed in the sensor compartments 154 and 155.

When an image 23 from the continuously moving film 13 is projected onto the viewing screen 39, the corresponding sprocket hole image 53 is projected onto the sensor aperture 164. The aperture 164 has a first portion 170 and a second portion 171. These two aperture portions are separated by the compartment wall 156. Light which penetrates the aperture portion 170 illuminates the photocell 158, while light which penetrates the aperture portion 171 illuminates the photocell 159. Accordingly, the combined photocells 154 and 159 provide zero net signal when equal amounts of light at like intensities penetrate the aperture portions 170 and 171.

As described above, it is advantageous to provide for a slight constant tracking error that imposes a substantially constant torque on the advancing compensator mirror 40. Accordingly, FIG. 10 shows an error signal 174 that is provided by the photocells 158 and 159 in response to the above mentioned constant tracking error. As also mentioned above, an electrical bias may be employed to bias the compensator mirror 40 in a direction opposite to the direction of mirror advance during image display. Slight fluctuations in the signal curve 174 illustrate signal variations that are applied to the amplifier 55 by the sensor 150 in order to stabilize the position of the projected image on the screen 39. If desired, an adjustable damping net work of the type shown at 60, 61 and 63 in FIG. 3 may be provided between the sensor 150 and the servo amplifier 55 in order to stabilize and/or adjust the operation of the compensator mirror 40.

The combined photocells 158 and 159 increase the positive amplitude of the error signal 175 shown in FIG. 10 when the projected sprocket hole image 53 moves downwardly so that more light reaches the photocell 1.59 through the aperture portion 171 than the photocell 158 through the aperture portion 170. Conversely, the combined photocells 158 and 159 decrease the amplitude of the error signal 174 when the projected sprocket hole image 53 moves upwardly so that more light reaches the photocell 158 through the aperture portion 170 than the photocell 159 though the aperture portion 171. The servo amplifier 55 energized the compensator drive coil 41 correspondingly, so that the projected image is stabilized in the above mentioned manner.

The projection and mirror reflection of the above mentioned light stimulus 79 produces on the face plate 162 of the sensor 150 an image 178 of the film gate aperture 78. The aperture image 178 moves in the direction of an arrow 176 as the display of the projected image by the advancing compensator mirror 40 progresses. The aperture 168 in the sensor 150 is so positioned that the projected aperture image 178 penetrates the aperture 168 and illuminates the photocell 158 when the mirror has reached, or is just about to reach, its ultimate advanced position 40' from which it is to be reset. This sudden illumination of the photocell 158 drives the error signal shown in FIG. 10 to a large negative value 180 which, in turn, causes the amplifier 55 to drive the mirror 40 rapidly in a backward direction. In consequence, the projected image on the screen 39 is replaced by a projection of the next-succeeding image 23 on the motion picture film 13. During such image replacement, the sprocket hole image 182 pertaining to the replacing image moves in the direction 183 onto the aperture 165 of the sensor 150. Light from the sprocket hole image 182 penetrates the aperture 165 to illuminate the photocell 158, thereby causing the sensor 150 to provide a large negative error signal 185. In response to that error signal, the servo amplifier 155 continues to reset the compensator mirror 40 preparatory to the display of the next-succeeding image 23 on the film 13.

While the sprocket hole image 182 of the nextsucceeding image is moving onto the aperture 165, the sprocket hole 53 of the last-displayed image is moved in the direction of the arrow 186 toward the aperture 166. During such downward travel of the sprocket hole image 53, the photocell 159 will be illuminated stronger by the sprocket hole image 53 than the photocell 158, since portions of that sprocket hole image which leave the. upper aperture portion 170 will move over the lower portion 171 before leaving the aperture 164 entirely. Where such stronger illumination of the photocell 159 would lead to a premature deceleration of the resetting operation of the mirror 40,

a compensation may be effected by a suitable configuration of the aperture 165, for instance. By way of example, FIG. 9 shows the aperture 165 as being larger in width than the aperture 164, so that the sprocket hole image 182 is capable of illuminating the photocell 158 through the aperture 165 stronger than the sprocket hole image 53 illuminates the photocell 159 through the aperture portion 171.

In the further course of its downward motion, the sprocket hole image 182 moves away from the aperture The sprocket hole image 53 leaves the aperture 166 in a'downward direction as the resetting mirror 40 positions the sprocket hole image 182 on the aperture 164. At about the same time, the image 178 of the auxiliary aperture 78 in the film gate 12 illuminates the photocell 159 through the aperture 167, thereby causing the sen.- sor 150 to produce a further positive error signal 191. The error signal 191 also causes the servo amplifier 55 to generate and apply decelerating energy to the mirror drive 41, so that the mirror 40 is further decelerated during its resetting operation.

A brief analytical review of the function of the aperture of FIGS. 8 and 9 will be helpful at this juncture. The servo amplifier 55 generates resetting energy when the reflected light stimulus 79 illuminates the photocell 158 through the aperture 168. That resetting energy is applied to the mirror drive 41 to initiate a resetting operation of the compensator mirror 40.

A second light stimulus in the form of the sprocket hole image 182 causes the generation of reset sustaining energy 185 by illumination of the photocell 158 1 through the aperture 165. The servo amplifier 55 ap- 165 and in the direction of the aperture 164. At the same time, the sprocket hole image 53 moves away from the aperture 164 and onto the aperture 166. This provides for a strong illumination of the photocell 159 by the sprocket hole image 53 which causes the sensor 150 to provide a large positive error signal 187. The amplitude of that error signal is eventually somewhat diminished by the illumination which the photocell 158 receives from the sprocket hole image 182, as that sprocket hole image starts to move onto the upper aperture portion 170. By a suitable design of the aperture 66 relative to-the aperture 164, the illumination provided by the sprocket hole image 53 at the photocell 159 can, however, still be made to dominate the illumination of the photocell 158 by the sprocket hole image 182 through the upper aperture portion 170.

The large positive error signal 187 causes the doubleended servo amplifier 55 (see FIG. 4 to generate and to apply tothe mirror drive 41 decelerating energy which prevents the mirror 40 from overshooting its range of motion in the resetting directionQOf course, care has to be taken that the generated decelerating energy does not prevent the compensator mirror 40 from completing its resettingoperation.

The energy content of the positive error signal 187 is controlled by a suitable design of the aperture 166. By way of example,FlG9 shows a trapezoidconfiguration for the aperture 166. In addition, the aperture 166 is provided in a member .189 which is slidable relative to the face plate 162 as indicated by the dotted lines 190. In this manner, it is possible to adjust the timing of the positive error signal 187. The slide 189 is preferably located ona hole in the face plate 162 which is larger than the aperture 166, but which is small enough so as not to be uncovered by the slide 189 when the same is moved upwardly or downwardly as indicated by the dotted outline 190.

plies that energy to the drive 41 in'order to sustain the resetting operation for a predetermined period of time determined by such factors as the location and design of the aperture 165. In practice, the generation of the reset sustaining energy in response to the sprocket hole image 182 may be omitted if the energy content of the resetting energy provided by the aperture image 178 is sufficient to reset the compensator mirror.

A further projected light stimulus in the form of the sprocket hole image 53, by means of which the previously projected image was stabilized on the screen, provides an error signal 187 when that light stimulus illuminates the photocell 159 through the aperture 166. The servo amplifier 55 generates decelerating energy which is applied to the drive 41 in order to decelerate the compensator mirror 40 preparatory to a display of a succeeding image. I The first light stimulus 79 also causes the servo amplifier to apply decelerating energy to the mirror drive 41 when that stimulus 79 illuminates the photocell 159 through the aperture 167. In practice, the generation of either the decelerating energy corresponding to the error signal 187 or the decelerating energy corresponding to the error signal 191 may be omitted if either the stimulus 79 or the stimulus represented by the sprocket hole image 53 is by itself capable of generating all the requisite decelerating energy.

In either of the stimuli combinations herein mentioned, the sensor will produce a resetting pulse doublet 194 composed of a negative pulse (see 195) and a positive pulse (see 196). The energy provided by the servo amplifier 55 in response to the negative pulse 195 will accelerate the compensator mirror 40 in its resetting direction, while the positive pulse'196 of the doublet 194 will cause the amplifier 55 to decelerate theresetting operation of the mirror 40,so that this compensator mirror is accurately positioned for an initiation of a display of the next image.

The sprocket hole image 182 having thus been substituted for the sprocket hole image 53, the display of the next-succeeding image takes place in the manner mentioned above for the image pertaining to the sprocket hole image 53, except that movements of the sprocket hole image 182 now control the advance of the compensator mirror 40, as indicated by the error signal 200.

The aperture logic and doublet generation of FIGS. 8 and 9 are greatly superior to complicated electronic approachesof the type disclosed in the Laser Display Study, by C. E. Baker and l-LW. Parker, Technical Report No. RADC-TR-65-169, July 1965, Display Techniques Branch, Rome Air Development Center, Griffiss Air Force Base, N.Y. pp. 31 to 36.

I claim:

1. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements, the improvement comprising in combination the steps of:

displaying each image by way of said compensator;

advancing said compensator during the display of each image to compensate for the continuous carrier movement; sensing an extreme advanced position of said compensator; and

resetting said compensator between successive advancements in response to each sensing of said extreme advanced position.

2. A method as claimed in claim 1, wherein:

said extreme advanced position of said compensator is sensed by providing a projectable stimulus, projecting said stimulus by way of said compensator, and sensing the projected stimulus to determine attainment of said extreme advanced position by said compensator.

3. A method as claimed in claim 1, wherein:

said extreme advanced position of said compensator is sensed by providing a projectable stimulus, projecting said stimulus by way of said compensator, and sensing a position of the projected stimulus indicative of an attainment of said extreme advanced position.

4. A method as claimed in claim 1, wherein:

said compensator includes a compensator mirror,

each image being displayed by way of said compensator mirror, said compensator mirror being advanced during the display of each image to compensate for the continuous carrier movement, and said compensator mirror being reset in response to each sensing of said extreme advanced position.

5. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements, the improvement comprising in combination the steps of:

displaying each image by way of said compensator;

advancing said compensator during the display of each image to compensate for the continuous carrier movement;

providing a projectable stimulus;

' projecting said stimulus by way of said compensator;

generating resetting energy for said compensator in response to said projected stimulus upon completion of the display of any image; and

resetting said compensator with said resetting ener- 6. A method as claimed in claim 5, wherein:

said projectable stimulus is made to emanate from a location substantially stationary relative to said moving carrier.

7. A method as claimed in claim 5, wherein:

said projectable stimulus is made movable with said moving carrier.

8. A method as claimed in claim 5, including the further steps of:

generating reset decelerating energy in response to said projected stimulus preparatory to the display of a succeeding image; and

decelerating the resetting compensator with said reset decelerating energy.

9. A method as claimed in claim 5, wherein:

said compensator includes a compensator mirror,

each image being displayed by way'of said compensator mirror, said compensator mirror being advanced during the display of each image to compensate for the continuous carrier movement, said stimulus being projected by way of said compensator mirror, and said compensator mirror being reset with said resetting energy.

10. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements, the improvement comprising in combination the steps of: I

displaying each image by way of said compensator;

advancing said compensator during the display of each image to compensate for the continuous carrier movement;

providing a first projectable stimulus;

providing a second projectable stimulus;

projecting said first and second stimuli by way of said compensator; v 1

generating reset initiation energy for said compensator in response to said first projected stimulus upon completion of the display of an image;

initiating a resetting operation of said compensator with said reset initiation energy;

generating reset sustaining energy for said compensator in response to said second projected stimulus; and

sustaining said initiated resetting operation of said compensator with said reset sustaining energy.

1 l. A method as claimed in claim 10, wherein:

said first projectable stimulus is made to emanate from a location substantially stationary relative to said moving carrier; and

said second projectable stimulus is made movable with said moving carrier.

12. A method as claimed in claim 10, including the generating reset decelerating energy in response to at least one of said first and third projected stimuli;

and v decelerating the resetting compensator with said decelerating energy preparatory to the display of a succeeding image. 14. A method as claimed in claim 13, wherein: said first projectable stimulus is made to emanate from a location substantially stationary relative to said moving carrier; and said second projectable stimulus is made movable with said moving carrier. 15. A method as claimed in claim 10, wherein: said compensator includes a compensator ,mirror, each image being displayed by way of said compensator mirror, said compensator mirror being advanced during the display of each image to compensate for the continuous carrier movement, said first and second stimuli being projected by way of said compensator mirror, said reset initiation energy initiating a resetting operation of said compensator mirror, and said reset sustaining energy sustaining said initiated resetting operation of said compensator mirror for a substantially predetermined period of time. I 16. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensatorof a type image to compensate for the continuous carrier movement; generating resetting energy for said compensator in response to said projected first stimulus upon completion of the display of any image; and resetting said compensator with said resetting ener- 17. A method as claimed in claim 16, including the further steps of:

generating reset decelerating energy in response to at least one of said projected first and second stimuli preparatory to the display of a succeeding image; and

decelerating the resetting compensator with said reset decelerating energy.

18. In apparatus for displaying images of a succession of recordings from a carrier, the improvement compris ing the combination of:

means for substantially continuously advancing said carrier;

means fordisplaying each of said images, including optical compensator means;

means for advancing said compensatormeans during the display of each image to compensate for the continuous carrier movement;

means for sensing an extreme advanced position of said compensator means; and means connected to said sensing means for resetting said compensator means between successive compensator means advancements in response to each sensing of said extreme advanced position.

19. Apparatus as claimed in claim 18, wherein:

said means for sensing an extreme advanced position of said compensator include means for providing a projectable stimulus, means for projecting said stimulus by way of said compensator means, and means for sensing the projected stimulus to determine attainment of said extreme advanced position by said compensator means.

20. Apparatus as claimed in claim 18, wherein:

said means for sensing an extreme advanced position of said compensator include means for providing a projectable stimulus, means for projecting said stimulus by way of said compensator means, and means for sensing a position of the projected stimulus indicative of an attainment of said extreme advanced position.

21. An apparatus as claimed in claim 18, wherein: said optical compensator means include a compensator mirror. 22. In apparatus for displaying images of a succession of optical recordings from a carrier, the improvement comprising the combination of:

means for substantially continuously advancing said carrier; 7

means for supporting said advancing carrier, said supporting means including a first aperture permitting a display of said images, and a second aperture;

means for illuminating. said first and second apertures and images passing through said first aperture; r

optical film motion compensator means;

means for displaying each illuminated image and light from said illuminated second aperture by way of said compensator means;

means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement;

means for sensing the attainment of an extreme advanced position by said displayed light from said illuminated second aperture; and

means connected to said sensing means for resetting said compensator means in response to each sensing of said attainment of an extreme advanced position by said displayed light from said illuminated second aperture.

23. Apparatus as claimed in claim 22, wherein: said optical compensator means is a rockable compensator mirror; said displaying means include means for displaying each illuminated image and light from said illuminated second aperture by way of said compensator mirror; said means for advancing said compensator means include means for angularly advancing said compensator mirror during the display of each image to compensate for the continuous carrier movement; and

- said means for resetting said compensator means include means for angularly resetting said compensator mirror in response to each sensing of said attainment of an extreme advanced position by said displayed light from said illuminated second aperture.

24. In apparatus for displaying images of a succession of recordings from a carrier, the improvement comprising the combination of:

means for substantially continuously advancing said carrier; 1 means for displaying each of said images, including optical compensator means;

means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement;

means for providing a projectable stimulus;

means for projecting said stimulus by way of said compensator means;

means responsive to said projected stimulus for generatingresetting energy for said compensator means upon completion of the display of any image; and

means connected ,to said generating means for resetting said compensator means with said resetting energy.

25. Apparatus as claimed in claim 24, wherein:

said means for providing a projectable stimulus include means for emitting said projectable stimulus from a location which is substantially stationary relative to said advancing carrier.

26. Apparatus as claimed in claim 24, wherein:

said means for providing a projectable stimulus include means for emitting said projectable stimulus form a location moving with said advancing carri- 27. Apparatus as. claimed in claim 24, including:

- means responsive to said projected stimulus for generating reset decelerating energy preparatory to the display of a succeeding image; and

means connected to said resetting means for decelerating the resetting compensator means with said decelerating energy preparatory to the display of said succeeding image. 1 28. Apparatus as claimed in claim 24, wherein: said optical compensator means include a compensator mirror.

29. In apparatus for displaying images of a succession of recordings from a carrier, the improvement comprising the combination of:

meansfor substantially continuously advancing said carrier; meansfor displaying each of said images, including optical compensator means;

means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement;

means for providing a first projectable stimulus;

means for providing a second projectable stimulus;

means for projecting said first and second stimuli by way of said compensator means;

means responsive to said projected first stimulus for generating reset initiation energy for said compensator means uponcompletion of the display of an image;

means connected to said initiation energy generating means for initiating to resetting operation of said lus include means for emitting said second projectable stimulus from a location moving with said advancing carrier. 31. Apparatus as claimed in claim 29, including: means responsive to at least one of said projected stimuli for generating decelerating energy preparatory to the display of a succeeding image; and

means connected to said resetting means for decelerating the resetting compensator means with said decelerating energy preparatory to the display of said succeeding image.

32. Apparatus as claimed in claim 29, wherein:

said means for advancing said compensator means during the display of each image include means for providing a third projectable stimulus moving with said advancing carrier, means for projecting said third stimulus by way of said compensatormeans, and means for controlling said compensato'rmeans advance in response to said projected third stimulus;

said apparatus includes means responsive to at least one of said first and third stimuli for generating reset decelerating energy preparatory to the dis play of a succeeding image; and

said apparatus includes means connected to said resetting means for decelerating the resetting compensator means with said decelerating energy preparatory to the display of said succeeding image.

33. Apparatus as claimed in claim 32, wherein: V

said means for providing a first projectable stimulus include means for emitting said first projectable stimulus from a location which is substantially stationary relative to said advancing carrier; and

said means for providing a second projectable stimulus include means for emitting said second projectable stimulus from a location moving with said advancing carrier.

34. Apparatus as claimed in claim 29, wherein:

said optical compensator means include a compensator mirror.

35. In apparatus for displaying images of a succession of recordings from a carrier, the improvement comprising the combination of:

means for essentially continuously advancing said carrier;

means for displaying each of said images, including optical compensator-means;

means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement;

means for providing a first projectable stimulus emanating from a location essentially stationary relative to said advancing carrier;

means for providing a second projectable stimulus emanating from a location moving with said advancing carrier;

means for projecting said first and second stimuli by way of said compensator means; 1

means responsive to said second projected stimulus for controlling said compensator means during the display of each image;

means responsive to said first projected stimulus for generating compensator resetting energy upon completion of the display of any image; and

means connected to said compensator means and to said reset energy generating means for resetting said compensator means with said resetting'ener- 36. Apparatus as claimed in claim 35, including: means for generating reset deceleration energy inresponse to said second projected stimulus preparatory to the display of a succeeding image; and means connected to said resetting means for decelerating the resetting compensator with said resetdecelerating energy. 37. Apparatus as claimed in claim 35, including; means for generating reset deceleration energy in response to said first projected stimulus preparatory to the display of a succeeding image; and means connected to said resetting means for decelerating the resetting compensator with said reset decelerating energy. 

1. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements, the improvement comprising in combination the steps of: displaying each image by way of said compensator; advancing said compensator during the display of each image to compensate for the continuous carrier movement; sensing an extreme advanced position of said compensator; and resetting said compensator between successive advancements in response to each sensing of said extreme advanced position.
 2. A method as claimed in claim 1, wherein: said extreme advanced position of said compensator is sensed by providing a projectable stimulus, projecting said stimulus by way of said compensator, and sensing the projected stimulus to determine attainment of said extreme advanced position by said compensator.
 3. A method as claimed in claim 1, wherein: said extreme advanced position of said compensator is sensed by providing a projectable stimulus, projecting said stimulus by way of said compensator, and sensing a position of the projected stimulus indicative of an attainment of said extreme advanced position.
 4. A method as claimed in claim 1, wherein: said compensator includes a compensator mirror, each image being displayed by way of said compensator mirror, said compensator mirror being advanced during the display of each image to compensate for the continuous carrier movement, and said compensator mirror being reset in response to each sensing of said extreme advanced position.
 5. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements, the improvement comprising in combination the steps of: displaying each image by way of said compensator; advancing said compensator during the display of each image to compensate for the continuous carrier movement; providing a projectable stimulus; projecting said stimulus by way of said compensator; generating resetting energy for said compensator in response to said projected stimulus upon completion of the display of any image; and resetting said compensator with said resetting energy.
 6. A method as claimed in claim 5, wherein: said projectable stimulus is made to emanate from a location substantially stationary relative to said moving carrier.
 7. A method as claimed in claim 5, wherein: said projectable stimulus is made movable with said moving carrier.
 8. A method as claimed in claim 5, including the further steps of: generating reset decelerating energy in response to said projected stimulus preparatory to the display of a succeeding image; and decelerating the resetting compensator with said reset decelerating energy.
 9. A method as claimed in claim 5, wherein: said compensator includes a compensator mirror, each image being displayed by way of said compensator mirror, said compensator mirror being advanced during the display of each image to compensate for the continuous carrier movement, said stimulus being projected by way of said compensator mirror, and said compensator mirror being reset with said resetting energy.
 10. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being resEt between successive advancements, the improvement comprising in combination the steps of: displaying each image by way of said compensator; advancing said compensator during the display of each image to compensate for the continuous carrier movement; providing a first projectable stimulus; providing a second projectable stimulus; projecting said first and second stimuli by way of said compensator; generating reset initiation energy for said compensator in response to said first projected stimulus upon completion of the display of an image; initiating a resetting operation of said compensator with said reset initiation energy; generating reset sustaining energy for said compensator in response to said second projected stimulus; and sustaining said initiated resetting operation of said compensator with said reset sustaining energy.
 11. A method as claimed in claim 10, wherein: said first projectable stimulus is made to emanate from a location substantially stationary relative to said moving carrier; and said second projectable stimulus is made movable with said moving carrier.
 12. A method as claimed in claim 10, including the further step of: generating reset decelerating energy in response to at least one of said projected stimuli preparatory to the display of a succeeding image; and decelerating the resetting compensator with said reset decelerating energy.
 13. A method as claimed in claim 10, including the further steps of: controlling the advance of said compensator during the display of each image with a third projectable stimulus which is movable with said moving carrier and which is projected by way of said compensator; generating reset decelerating energy in response to at least one of said first and third projected stimuli; and decelerating the resetting compensator with said decelerating energy preparatory to the display of a succeeding image.
 14. A method as claimed in claim 13, wherein: said first projectable stimulus is made to emanate from a location substantially stationary relative to said moving carrier; and said second projectable stimulus is made movable with said moving carrier.
 15. A method as claimed in claim 10, wherein: said compensator includes a compensator mirror, each image being displayed by way of said compensator mirror, said compensator mirror being advanced during the display of each image to compensate for the continuous carrier movement, said first and second stimuli being projected by way of said compensator mirror, said reset initiation energy initiating a resetting operation of said compensator mirror, and said reset sustaining energy sustaining said initiated resetting operation of said compensator mirror for a substantially predetermined period of time.
 16. In a method of displaying images of a succession of recordings from a substantially continuously moving carrier, with the aid of an optical compensator of a type being repeatedly advanced and being reset between successive advancements, the improvement comprising in combination the steps of: providing a first projectable stimulus emanating from a location substantially stationary relative to said moving carrier; providing a second projectable stimulus being movable with said moving carrier; displaying each image, and projecting said first and second stimuli, by way of said compensator; advancing said compensator, and controlling the advance of said compensator in response to said projected second stimulus during the display of each image to compensate for the continuous carrier movement; generating resetting energy for said compensator in response to said projected first stimulus upon completion of the display of any image; and resetting said compensator with said resetting energy.
 17. A method as claimed in claim 16, including the further steps of: generating reset decelerating energy in response to at least one of said projected fIrst and second stimuli preparatory to the display of a succeeding image; and decelerating the resetting compensator with said reset decelerating energy.
 18. In apparatus for displaying images of a succession of recordings from a carrier, the improvement comprising the combination of: means for substantially continuously advancing said carrier; means for displaying each of said images, including optical compensator means; means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement; means for sensing an extreme advanced position of said compensator means; and means connected to said sensing means for resetting said compensator means between successive compensator means advancements in response to each sensing of said extreme advanced position.
 19. Apparatus as claimed in claim 18, wherein: said means for sensing an extreme advanced position of said compensator include means for providing a projectable stimulus, means for projecting said stimulus by way of said compensator means, and means for sensing the projected stimulus to determine attainment of said extreme advanced position by said compensator means.
 20. Apparatus as claimed in claim 18, wherein: said means for sensing an extreme advanced position of said compensator include means for providing a projectable stimulus, means for projecting said stimulus by way of said compensator means, and means for sensing a position of the projected stimulus indicative of an attainment of said extreme advanced position.
 21. An apparatus as claimed in claim 18, wherein: said optical compensator means include a compensator mirror.
 22. In apparatus for displaying images of a succession of optical recordings from a carrier, the improvement comprising the combination of: means for substantially continuously advancing said carrier; means for supporting said advancing carrier, said supporting means including a first aperture permitting a display of said images, and a second aperture; means for illuminating said first and second apertures and images passing through said first aperture; optical film motion compensator means; means for displaying each illuminated image and light from said illuminated second aperture by way of said compensator means; means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement; means for sensing the attainment of an extreme advanced position by said displayed light from said illuminated second aperture; and means connected to said sensing means for resetting said compensator means in response to each sensing of said attainment of an extreme advanced position by said displayed light from said illuminated second aperture.
 23. Apparatus as claimed in claim 22, wherein: said optical compensator means is a rockable compensator mirror; said displaying means include means for displaying each illuminated image and light from said illuminated second aperture by way of said compensator mirror; said means for advancing said compensator means include means for angularly advancing said compensator mirror during the display of each image to compensate for the continuous carrier movement; and said means for resetting said compensator means include means for angularly resetting said compensator mirror in response to each sensing of said attainment of an extreme advanced position by said displayed light from said illuminated second aperture.
 24. In apparatus for displaying images of a succession of recordings from a carrier, the improvement comprising the combination of: means for substantially continuously advancing said carrier; means for displaying each of said images, including optical compensator means; means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement; means for Providing a projectable stimulus; means for projecting said stimulus by way of said compensator means; means responsive to said projected stimulus for generating resetting energy for said compensator means upon completion of the display of any image; and means connected to said generating means for resetting said compensator means with said resetting energy.
 25. Apparatus as claimed in claim 24, wherein: said means for providing a projectable stimulus include means for emitting said projectable stimulus from a location which is substantially stationary relative to said advancing carrier.
 26. Apparatus as claimed in claim 24, wherein: said means for providing a projectable stimulus include means for emitting said projectable stimulus form a location moving with said advancing carrier.
 27. Apparatus as claimed in claim 24, including: means responsive to said projected stimulus for generating reset decelerating energy preparatory to the display of a succeeding image; and means connected to said resetting means for decelerating the resetting compensator means with said decelerating energy preparatory to the display of said succeeding image.
 28. Apparatus as claimed in claim 24, wherein: said optical compensator means include a compensator mirror.
 29. In apparatus for displaying images of a succession of recordings from a carrier, the improvement comprising the combination of: means for substantially continuously advancing said carrier; means for displaying each of said images, including optical compensator means; means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement; means for providing a first projectable stimulus; means for providing a second projectable stimulus; means for projecting said first and second stimuli by way of said compensator means; means responsive to said projected first stimulus for generating reset initiation energy for said compensator means upon completion of the display of an image; means connected to said initiation energy generating means for initiating to resetting operation of said compensation means with said reset initiation energy; means responsive to said projected second stimulus for generating reset sustaining energy for said compensator means; and means connected to said sustaining energy generating means for sustaining said initiated resetting operation of said compensator means with said reset sustaining energy.
 30. Apparatus as claimed in claim 29, wherein: said means for providing a first projectable stimulus include means for emitting said first projectable stimulus from a location which is substantially stationary relative to said advancing carrier; and said means for providing a second projectable stimulus include means for emitting said second projectable stimulus from a location moving with said advancing carrier.
 31. Apparatus as claimed in claim 29, including: means responsive to at least one of said projected stimuli for generating decelerating energy preparatory to the display of a succeeding image; and means connected to said resetting means for decelerating the resetting compensator means with said decelerating energy preparatory to the display of said succeeding image.
 32. Apparatus as claimed in claim 29, wherein: said means for advancing said compensator means during the display of each image include means for providing a third projectable stimulus moving with said advancing carrier, means for projecting said third stimulus by way of said compensator means, and means for controlling said compensator means advance in response to said projected third stimulus; said apparatus includes means responsive to at least one of said first and third stimuli for generating reset decelerating energy preparatory to the display of a succeeding image; and said apparatus includes means connected to said resetting means fOr decelerating the resetting compensator means with said decelerating energy preparatory to the display of said succeeding image.
 33. Apparatus as claimed in claim 32, wherein: said means for providing a first projectable stimulus include means for emitting said first projectable stimulus from a location which is substantially stationary relative to said advancing carrier; and said means for providing a second projectable stimulus include means for emitting said second projectable stimulus from a location moving with said advancing carrier.
 34. Apparatus as claimed in claim 29, wherein: said optical compensator means include a compensator mirror.
 35. In apparatus for displaying images of a succession of recordings from a carrier, the improvement comprising the combination of: means for essentially continuously advancing said carrier; means for displaying each of said images, including optical compensator means; means for advancing said compensator means during the display of each image to compensate for the continuous carrier movement; means for providing a first projectable stimulus emanating from a location essentially stationary relative to said advancing carrier; means for providing a second projectable stimulus emanating from a location moving with said advancing carrier; means for projecting said first and second stimuli by way of said compensator means; means responsive to said second projected stimulus for controlling said compensator means during the display of each image; means responsive to said first projected stimulus for generating compensator resetting energy upon completion of the display of any image; and means connected to said compensator means and to said reset energy generating means for resetting said compensator means with said resetting energy.
 36. Apparatus as claimed in claim 35, including: means for generating reset deceleration energy in response to said second projected stimulus preparatory to the display of a succeeding image; and means connected to said resetting means for decelerating the resetting compensator with said reset decelerating energy.
 37. Apparatus as claimed in claim 35, including; means for generating reset deceleration energy in response to said first projected stimulus preparatory to the display of a succeeding image; and means connected to said resetting means for decelerating the resetting compensator with said reset decelerating energy. 